Silicone rubber composition

Abstract

A silicone rubber composition having good processability and good molding properties is disclosed, said composition comprising: (A) an organopolysiloxane containing vinyl groups; (B) a fluorine resin powder; (C) an organopolysiloxane containing units having the formula F(CF.sub.2).sub.a CH.sub.2 CH.sub.2 Si(Me).sub.n O.sub.3-n/2 in which a is an integer of at least 4, n is 0, 1 or 2 and Me denotes a methyl radical; (D) a reinforcing silica powder having a surface area of at least 50 m 2 /g; and (E) a sufficient quantity of a curing agent to cure said composition.

That which is claimed is: 
     
       1. A silicone rubber composition comprising: (A) 100 parts by weight of an organopolysiloxane containing vinyl groups;   (B) 0.01 to 50 parts by weight of a fluorine resin powder;   (C) 0.01 to 40 parts by weight of an organopolysiloxane represented by the formula ##STR3## in which a is an integer of at least 4, Me denotes a methyl radical, p and q are integers having a value of at least 1 and (p+q) is 3 to 40;   (D) 10 to 100 parts by weight of a reinforcing silica powder having a surface area of at least 50 m 2  /g; and   (E) a sufficient quantity of a curing agent to cure said composition.   
     
     
       2. The composition according to claim 1, wherein a is 4 to 8. 
     
     
       3. The composition according to claim 2, wherein said fluorine resin powder (B) is polytetrafluoroethylene. 
     
     
       4. The composition according to claim 2, wherein said organopolysiloxane (A) is selected from the group consisting of dimethylpolysiloxane having terminal dimethylvinylsiloxy groups, copolymers of dimethylsiloxane and methylvinylsiloxane having terminal dimethylvinylsiloxy groups, copolymers of dimethylsiloxane and methylvinylsiloxane having terminal trimethylsiloxy groups and copolymers of dimethylsiloxane and methylvinylsiloxane having terminal dimethylhydroxysiloxy groups.